Assessment of mitochondrial membrane potential (∆ψM)

Mitochondrial membrane potential was assessed with the fluorescent dye JC-1 Mitochondrial Membrane Potential Detection kit (Stratagene) and confocal microscopy following the manufacturer’s instructions. In brief, cells were incubated with 1×JC-1 reagent solution at 37°C for 15 min. Culture slides were washed and mounted with PBS, and confocal images were acquired by the Carl Zeiss LSM 700 Meta confocal microscope. The red-to-green fluorescence ratio was quantified from cells of interest using the measurement functions on the confocal microscopy software.